This invention relates to vision improvement and to the improvement of depth perception in particular for individuals having eyes of unequal vision acuity by improving stereoscopic vision through the use of rapidly operating shutters.
The invention provides for the subduing of the stronger eye by means of an electronic shutter to compensate for the brain's ability to ignore the weak eye information, thus improving binocular eyesight. The stronger eye may individually be subdued by the shutter or vision may be provided as alternating between eyes according to a duty cycle wherein the weaker eye can be exposed for a longer duration than the stronger eye. Thus, usage of the weaker is promoted. The control of vision by each eye is also useful in treating lazy eye, a condition in which the brain begins to ignore information from one eye.
Depth perception is acquired by a number of mechanisms, including psychologic monocular and binocular visual information processed by the brain. Binocular mechanisms obtained through stereoscopic vision are well understood for their role in depth perception. Views from either the righthand side or lefthand side individual eyes produces slightly dissimilar images due to the different vantage points resulting from the lateral separation between the eyes. The simultaneous viewing of these disparate views is what produces the perception of depth. The perception of depth is maintained as long as both eyes are used. If either eye is closed or unused, however, the perception of depth vanishes.
Stereoscopic vision is well understood in the art and forms the basis for stereoscope pictures and three-dimensional vision simulation employing special glasses for separating right and left images to create the perception of depth. Recent embodiments of three-dimensional viewing glasses for use with synchronized stereoscopic display systems have utilized rapid electronic shutters, such as liquid crystal shutters, wherein left eye and right eye images are presented alternatively. See e.g., Noble, U.S. Pat. No. 4,907,860 entitled "Three Dimensional Viewing Glasses" issued Mar. 13, 1990, and Kilian, U.S. Pat. No. 5,245,319 entitled "Synchronized Stereoscopic Display System" issued Sep. 14, 1993. Known glasses for this purpose rapidly alternate vision from one eye to the other allotting an equal time window through which each respective eye is exposed in turn presenting images corresponding to the particular viewing eye.
Such eyeglasses, having rapidly alternating shutters, have also been employed for use in the treatment and diagnosis of certain malfunctions of the eye as well, including malfunctions involving the phenomenon of suppression, such as strabismus (crossed-eye) and amblyopia (lazy eye) wherein one of an individual's eyes is effectively blind through suppression despite actually having the capability for vision. Eyeglasses for alternating vision from one eye to the other in equal time allotments are disclosed in Hussey U.S. Pat. No. 5,264,877 entitled "Eyeglasses For Use In The Treatment/Diagnosis Of Certain Malfunctions Of The Eye" issued Nov. 23, 1993.
There are individuals who do not suffer from suppression but merely have one eye sufficiently weaker in acuity than the other eye such that for the purpose of depth perception the brain tends to ignore information from the weaker eye effectively undermining the ability to perceive depth, although vision from the weaker eye is not altogether suppressed. For such individuals, the use of the eyeglasses taught by Hussey, which merely alternate vision from eye to eye, may not improve depth perception because, given equal time allotments, the brain naturally gives preference to information viewed from the better of the two eyes.
While known techniques for forcing the use of the weaker eye employ eye patches and the like to prevent usage of an eye for a predetermined treatment period, such techniques, while effective, are unpopular and physically unattractive. Moreover, such techniques effectively inhibit depth perception during treatment.